Photographic camera



Filed Oct.

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Patented Sept. 1, 1936 UNITED STATES PATENT OFFICE Application October9, 1935, Serial No. 44,182 In Germany September 5, 1934 4 Claims. (01.95-10) This invention relates to improvements in photographic cameras.

' The invention has particular reference to cameras having permanentlyassociated therewith an electric photometer, the circuit of which is adjustable inaccordance with other camera adjustments made. Cameraadjustments of this character are the adjustment of the aperture of thediaphragm, the speed of the shutter, and the sensitiveness of the plateor film used.

It is, therefore, an object of the present invention to facilitate theadjustment of the shutter to the proper speed by bringing the shutterinto a certain correlation to the electric photoml6 eter, causing anindicator of the latter to assume a predetermined position when theshutter speed has been set in accordance with the intensity of theprevailing light.

It is also an object of the invention to facilitate to generate electriccurrent with a resistance 10- cated in said current and variable inaccordance with the adjustment of movable elements of the camera, as forinstance with the positions of the diaphragm adjusting member or withthe position a of the shutter setting member or with both.

with these and other objects in view, an embodiment of the invention isillustrated in the accompanyin drawing by way of example.

The specification makes reference to this draw- 1 18.

In the drawing:

Fig. 1 is a cross-sectional view and partly top plan view of a cameraequipped with the electric photometer of this type, and

Fig. 2 is a front elevation of this camera.

The camera comprises a casing i which is equipped at the front wall witha detachable mounting 2 for a lens. The focal adjustment of the lens maybe secured by relative rotation of the mounting 2, the screw-threads ofthe bushing or sleeve 2. I

Detachable mountings for lenses of this type are well known inconnection with photographic cameras, and their attachment means oroptical equipment are, therefore, not-illustrated in the drawing. Thediaphragm (not shown) may be set to selectively predetermined aperturesby means of a ring or annular disc 4 having a pointer 5 which is adaptedto play over an aperture dial 6 on the lens mounting. The adjustingmember 4 for the diaphragm in the present em- 5 bodiment also serves asa carrier for a resistance 1 in the form of a flat coil or the likehaving the individual resistance elements bare on one surface, so thatthese elements upon rotatable adjustment of the ring 4 are successivelyengaged 10 by a contact member 8. i

The shutter is conventionally indicated as a curtain or slit shutter 9in operative connection with a knob I0 through bevel gears ii, I2, theknob being preferably disposed on the front wall 5 of the cameraadjacent the exchangeable lens mounting. The knob is equipped withascale carrying member l3 adapted to move successively the speedindications on said member into apposition with a fixed mark i4 also onthe front of the camera. This member l2 for setting the shutter to apredetermined speed also is connected with the slidable contact element8 through a train of gears i5, i6, i1 and i8.

The electric photometer also permanently associated with the camera i inthe embodiment illustrated in the drawing, comprises a plurality of flatelements 20 superposed and adapted to generate an electric current whenenergized by light. This assembly of photosensitive layers is preferablypositioned directly to the rear of an opening in the front wall, whichopening may be covered by a transparent element 2| having prismaticprojections for the purpose of deflecting the rays of light uniformlyagainst the assembly of photo.- sensitive layers 20. The resistance 1whose position relatively to the contact element I will be varied uponmovement of the diaphragm setting a member 4 is connected in the circuitof the current produced by this photoelectric cell or assembly 20. Thesame circuit also contains a current indicating instrument (not shown)having two terminals 22 and 23, and a pointer 24. An opening 25 in thetop wall of the camera permits the user to observe the position of theindicator 45 2|; the photometer also is provided with a fixed mark 26visible through said opening 25.

In the use of the device, the detachable mounting 2 of the lens isadjusted within the screwthreaded bushing 3 to focal-exactness as de- 50sired, and the diaphragm aperture is selected by rotating the member 4until the pointer 5 is in opposition to the desired aperture indication6 on the fixed scale. After the selection of the diaphragm aperture, theshutter setting member speed of the shutter has been efiected withrespect to the diaphragm opening previously seiected.

I claim: i

i. In a camera, the combination of an electric photometer, a shutter, ashutter setting member, a contact element actuated thereby, a resistancein the circuit of the electric photometer, and means for varying theposition of the resistance relatively to the contact member, the contactelement being in permanent variable engagement with said resistance,whereby the indi cations of the photometer are varied in accordance withthe position oi the shutter setting member and the position of saidresistance. 2. In a camera, the combination of an electric photometer, ashutter, a shutter setting member, a movable diaphragm setting element,a resistance in the photometer circuit carried by.said element, and acontact element actuated by the shutter setting member and in engagementwith aocaosle the resistance, whereby the indications oi the photometerare varied in accordance with the position of the diaphragm settingelement and the shutter adjusting member.

3. In a camera, the combination of an electric photometer, a resistancein the circuit of said having a fixed mark and a movable indicating 29member whose position is varied when said our tainshutter adjustingmeans is operated, Whereby the correct shutter adjustment is obtainedwhen said movable indicating member points to 25 said fixed mark.

HEINZ PENBENDER.

